ROOT ROT AND POWDERY MILDEW OF SUNFLOWER
- 1. STUDENT COURSE TEACHER RAMYA.V Dr. S. PARTHASARATHY ID. No. 2016021037 Assistant Professor (Plant Pathology). COLLEGE OF AGRICULTURAL TECHNOLOGY Affiliated to Tamil Nadu Agricultural University, Coimbatore Kullapuram, Via Vaigai dam, Theni-625 562 ROOT ROT AND POWDERY MILDEW OF SUNFLOWER
- 3. ROOT ROT SIGNIFICANCE • It is also called as charcoal rot. • It has wide host range responsible loses on more than 500 cultivated and wild plant species. • In pakistan, it has been reported to cause disease on 67 economic host including pulses, field crops, flowers and vegetables. • It is soil , seed and stubble borne fungal pathogen.
- 4. • 24 sunflower genotypes were analyzed under charcoal rot stress conditions. • Loses are often associated with hot and drought conditions. • It attacks 400 plant such as soybean ,edible beans, corn and sorghum.
- 5. HISTORY • Charcoal rot of sunflower was first reported in 1927 in Srilanka. • The scientist who gave name Macrophomina phaseolina is (Tassi) Goidanich in 1947. • The disease spread severe at Sahiwal in 1999 • In 2014, wilting of sunflower plants with silver grey lesions surrounding the lower stems were collected from Baicheng, Jinlin Province and Inner Mangolia Region.
- 6. ECONOMIC LOSSES • This disease cause yield reduction decrease of wait of 1000 seeds, decrease of the protein content in seeds and changes in the fatty acid content of the seed oil. • Yield reduction upto 50%
- 7. DISTRIBUTION • WORLD: Warmer region of Europe, Sahiwal, Slovakia. • In the former, USSR, the charcoal rot was registered in Russia(Northern Caucasus, Central Black Soil Zone), Ukraine and moldova. • INDIA: Punjab and Sindh.
- 8. SYMPTOMS • The pathogen attacks the root and stem of the growing plant causing sudden wilting of the plant. • Early symptom is not visible on infected plants, but the plant becomes weak, mature early and when dry show a presence of black ashy discolouration of the plant. • This pathogen primarily causes seedling blight and collar rot in initial stages. • The infected plants show drooping of leaves and death occurs in patches.
- 9. • The bark of the lower stem and root shreds and associated with large number of sclerotia. • Dark coloured minute picnidia also develop on the lower portion of the stem.
- 10. ROOT ROT OF SUNFLOWER www.eagri.org
- 11. Kingdom Fungi Phylum Ascomycota class Incertae sedis order Incertae sedis Family Incertae sedis Genus Macrophomina Species M.phaseolina SYSTEMIC POSITION
- 12. PATHOGEN -CHARACTERS • It was caused by fungal pathogen Macrophomina phaseolina . • This pathogen developing only during anamorphous stage in its life cycle. • The morphological structures of the pathogen are vegetative mycelium and sclerotia. • It also has a stage of sterile mycelium (Rhizactonia bataticola) • The central cylinder of the affected tissue numerous black small sclerotia are formed. • The slerotia size varies from 50-200 mkm.
- 13. • The pycnidia are dark brown to black with an ostiole and contain numerous single celled thin walled, hyaline and elliptical pycnidiospores. • Microsclerotia are black, smooth and round to obong in shape, uniformly reticulate, formed from hyphal aggregates. • Pycnidia are immersed in host tissue and aerumpent when mature.
- 14. • They are dark to greyish, globose and truncate ostiole. • Pycnidiospores are hyaline and single celled, ellipsoidal or ovoid, with a length-width ratio of 3:1.
- 15. MYCELIUM CHARACTERS • Hyphal branches are formed in a right angle and may form a cross wall at the constriction point.
- 16. PYCNIDIUM OF ROOT ROT www.biologydiscussion.com
- 19. EPIDEMOLOGY MODE OF SPREAD Primary spread • The pathogen is seed- borne and it serves as primary source of infection. • m the infected heads land on the later emerging florets and infect the frequent rain showers, high humidity and temperature. The disease is internally seed borne, where pathogen infects the embryo in the seed.
- 20. Secondary spread • Wind- borne conidia cause secondary spread. • The soil borne sclerotia also spreads through rain splash , irrigation water and implements.
- 21. FAVOURABLE CONDITIONS • Charcoal rot thrives in the hottest, driest part of the growing season. • Moisture stress and higher temperature favour development of the disease.
- 22. MANAGEMENT • Closer planting of the seedling should be avoided. • Optimum nutrition should be provided to maintain the plant vigour. • Whenever the soil becomes dry and the soil temperature rises then irrigation should be provided. • Seed treatment with Trichderma viride formulation at 4g/kg seed. • In endemic areas long crop rotation should be followed. • Treat the seeds with carbendazim or thiram at 2g/kg. • Spot drench with carbendazim at 500mg/litre.
- 23. POWDERY MILDEW SIGNIFICANCE • This disease is caused by Erysiphe cinchoracearum . • This disease responsible for economic losses in number of crops. • This disease has a limited range of host species. • This incidence of this disease is more severe in closely planted crops. • It is common in both irrigated and non irrigated conditions. • The most susceptible cultivar is Mega 363.
- 24. ECONOMIC LOSS: • Severity of disease leads to potential decrease in seed yield to an extract of 13 per cent. • Yield reduction is characterized by the reduction in photosynthetic activity and physiological changes. • Disease causing considerable yield loss proportional to the disease severity and the stage at which it occurs.
- 25. DISTRIBUTION • World: Pakistan, Romania, Serbia, USSR. • India: Bombay, Rajasthan, West bengal, Punjab.
- 26. SYMPTOMS • The first symptom are tiny, white superficial spots on leaves and stems which become powdery as they enlarge. • White powdery growth appears on the upper surface of the leaves and later on they enlarge, coalesce and cover the leaves. • Occassionaly, the symptoms appear on stems and bracts. • Severe infection may lead to premature defoliation of the plant. • The fruits remain undersized.
- 27. POWDERY MILDEW OF SUNFLOWER www.pnwhandbooks.org
- 28. SYSTEMIC POSITION Kingdom Fungi Phylum Ascomycota Class leotiomycetes Order Erysiphales Family Erysiphaceae Genus Erysiphev Species cichoracearum
- 29. PATHOGEN -CHARACTERS • The fungus, reported to overwinter as chasmothecia on plant residue. • Conidia in long chains, are ellipsoid to barrel-shaped . • Cleistothecia are formed in autumn, gregarious or scattered, globose, becoming depressed or irregular, wall cells usually indistinct, 10-20mm wide. • Appendages are numerous, basally inserted myceloid, interwoven with mycelium, hyaline to dark brown, 1- 4 times as long as the diameter of the ascocarp, rarely branched. • Asci 10-25, ovate to broadly ovate, rarely subglobose, more or less stalked.
- 30. MYCELIUM CHARACTERS • Mycelium is usually well developed and evanescent, but sometimes persistant and effused.
- 33. EPIDEMOLOGY MODE OF SPREAD • The disease develops strongly under dry conditions, at moderate to high levels of available nitrogen. • If ascomycota are formed, the fungus may survive a limited period of time in soil.
- 34. FAVOURABLE CONDITIONS • Conditions that favour the host, also favour the pathogen. • Spores germinate optimally at 20-25°C under conditions of high humidity, as quickly as two to four hours after landing on the leaf. • Under potimal conditions, infection will lead to the production of more spores within five to seven days.
- 35. MANAGEMENT • Dusting the crop with powdery sulphur @ 15.0 kg per hectare or spraying the crop with any one of the following fungicides is effective to control the disease. • Neem oil effectively manages powdery mildew on many plants by interfering with the fungus metabolism and terminating spore production.
- 36. • Sulfur and fish oil + sesame oil are effective bio fungicides that act against powdery mildew. • Pm3 allel is an effective genetic resistance strategy that protects host species against powdery mildew fungus.
- 37. REFERENCES • Das,P.C.2018.Plant Diseases. Kalyani Publishers,New Delhi. • Mehrotra,R.S and Ashok Aggarwal.2017.Plant Pathology.McGraw Hill Education (India) Private Limited,Chennai.